It's a Colt. The last patent date is July 4, 1905. The front sight has been modified, has custom hand made grips, the emblem inset on the right grip seems to be gold. It's had some very good trigger work but it was done long, long ago. It has seldom been fired but does show holster wear. Serial number (all match) is 88XXX.

Looks like the Colt Official Police .38 Special I have with a different front sight and grips. Looks to be in a hellava lot better shape than mine though. My great-grand father carried one as a police officer in the 30’s or 40’s. Beyond that all I know is that they shoot more accurately with hand loads than with factory ammo.

Quoted: Looks like the Colt Official Police .38 Special I have with a different front sight and grips. Looks to be in a hellava lot better shape than mine though. My great-grand father carried one as a police officer in the 30’s or 40’s. Beyond that all I know is that they shoot more accurately with hand loads than with factory ammo.

It's not that. for sure. It's BIG and a 45acp. It looks just like the New Service but I think the serial number is too early for that.

Any ideas on what the emblem is? I'm afraid to speculate.

It's a Colt new service made in 1915.  Odds are it was in .455 Ely, and converted to .45ACP later in life.  Obviously the .45ACP original ones didn't come around until 1917, because they were developed for US use in WWI.  Also the barrel is wrong for a 1917 because it's not a taper profile.  New Services after the Great War went to the newer profile.  

Since the sight is not original, somebody has definately worked on the gun.  It's not too great a leap to assume that the gun was rechambered at the same time.  This was very common with the .455 Ely New Services as .455 ammo became scarce.  The conversion entailed simply machining off the rear of the cylinder so the gun would take half-moon clips.  Take a close look at the cylinder face.  You will probably notice some milling marks.  A gun from Colt at the time wouldn't leave the factory with any marks there.  Alternatively, it could be a .45 Colt that had the cylinder replaced with a 1917 cylinder.  Either way the bore size is going to probably be .455 with that older style barrel.  Pre-war the .45 Colts used .455, and post-war (WWI) they used .452.  If you get erratic accuracy, like a flyer every once in a while, this could be the culprit.  

Are there any other markings?

As for the emblem, it's just the coat-of-arms of the USA.  Other than that, it has no significance other than someone wanted it on there.  Military New Services, the M1917 and the M1909 will state which model and what service (U.S.Army, USN, USMC) on the bottom of the grip frame.  You'll have to pull the grips off to see if anything is there with those grips.

The New Service frame was only used on the New Service and the Shooting Master.  The later had adjustible rear sights, so you do indeed have a New Service.  New Service serial numbers start at 1, in 1898, so ANY serial number is not too early.

Okay, here's some more. It had a lanyard hole but NO serial # or other marks on the base of the handle. On the left side of the handle is a 6 at the bottom and what looks like a capital I up near the spring. On the right side opposite the 6 is a two. These are probably just inspection marks. Here is the left view with some blow ups of the markings which you may or may not be able to make out.

Yeah, they're just inspection marks.  I don't know who they stand for.  The lanyard hole would indicate a likely military contract British gun.  When the British entered WWI in 1914, they needed guns, so they contracted Colt to furnish the New Service in .455.  This, combined with the 1915 date, and the barrel profile leads me to guess that this is probably one of those guns.  They are quite common for a New Service, and the conversion to .45ACP is equally common.  I think it was once estimated that they made about 50,000 in .455 all together.  You'll have to remember that not only wartime production, but just civillian use in Britain, Canada, and any of the Commonwealth nations would favor a .455 chambering.

So my guess is that it's a British WWI contract pistol in .455 that's been converted to .45ACP later in life at the same time the front sight was changed.

The 1905 patent date indicates that it is equipped with the saftey trigger block, which just means that the gun won't go off unless the trigger is pulled.  You'll notice that if you start to thumbcock the hammer, and it slips, the hammer won't go all the way down.  The firing pin will never proturde out the hole in the frame (you can see it on an empty pistol of course).  When the trigger is pulled all the way back, the hammer is free to go forward to fire.

Ross