Found a super condition SP-1 for 1400.00. serial # is SP1735x. But the upper doesn't have any markings on the right side, under the rear sight to indicate manufacturer. Most Colt's have a "C  M" I looked on biggerhammer.net and checked out the upper reciever pics. Some early receivers didn't have manufacturers markings according to them. This isn't a real early rifle.Is this a Colt receiver? Or a rebuild? Bolt is Colt, barrel is Colt, marked c  mp. Upper and lower receivers colors are not the same. But that seems to be pretty common, even in all original rifles. Thanks for any advice...

andrew...does it have a slickside receiver or does it have a forward assist?  Almost all SP1's are slicksided but a few have an FA on them.....I am still trying to determine how mine turned out that way...looks factory....I will check my upper later and get back to you on whether or not I have any markings.

It's a slickside

Even if it is all original, I think the price is a bit on the high side. They average around $1100 on the auctions.

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The only hope you have is to accept the fact that you are already dead. And the sooner you accept that, the sooner you will be able to function as a soldier is supposed to function, without mercy, without compassion, without remorse.

So. If he loves it, he loves it.

The one you're looking at was made in 1971 acorrding to the serial number.  It would almost (I say almost because that's the bet you can do wtih Colt) definately be without a forward assist.  Also check to see if it has a bolt-type front pivot pin.  An upper from this era would almost definately be a large hole upper.  If it's using an offset pivot pin, then it's probably not original.

Most AR parts, especially barrels, that were available for quite some time were only Colt.  It could be that someone's monkey'd with it in the past, but if it's a large hole upper (that someone didn't make by drilling out a small hole) then the odds are higher that it's original.

A common thing to do with SP-1s (which were about the only ARs around at the time) was to swap a USGI upper onto one to have a forward assist.  This was VERY common back then.  Could be this had it's original upper swapped off, then the current one placed on it when the original owner decided to sell it.  It really depends on how bad a mismatch the color is.  Colts don't match perfectly, but they are close.  Not like a purple BM upper and a grey lower or something.

How can you tell for sure?  I dunno.  Colt's alway have an exception to the rule.  If you don't feel right about it, then go with your gut.  At $1400, you can find plenty of nearly new genuine SP-1s.  That's not a great price.  If you love it, it's not too high, but if you're having doubts to it's authenticity, it's too high to chance.  You can take that $1400 and buy one you know is all Colt SP1 in a heartbeat, so don't be afraid to walk on this one.

Ross