Need help with 1,2,5,6

1 P17  or commercial model
2, 2 and 4 look to be Remington BDL's
5 & 6 are ADL's

Thank you

I take it #2 is just a different generation of BDL given the different checkering?

Yeah, look at pics online and you will see different patterns of checkering. 

The manufacturer name and caliber should be stamped on the barrel.  On guns newer than 1968 there should be a serial stamped onto the receicer on the side or on the bottom near the trigger guard.   Even on guns older than 1968 many will still have serial number and almost every gun I’ve seen during the modern era has the name stamped somewhere.  Some times rust or just filth can partially obscure the markings.

Many times people will get a picture like this from a relative and ask what guns they have.  It makes it a lot easier to identify if there are closeup photos of any proof marks or stamped names or numbers.