Unless you are getting this cheap, you'd do well to find a complete gun and go from there. Especially if you are new to the 1911. Does the frame have the FP safety lever? Sort of makes me wonder about the frame, because the frames are usually kept and the slides replaced. If the frame is for sale I wonder if something is wrong, spec wise ot otherwise.
I don't buy "part" of a gun unless it's dirt cheap, because I am always suspicious of the reason it is sold. That goes double for the 1911. If you do buy it, I guess you should first conver the frame parts to a s-70 config, lose the lever and assoc.parts, put in a spacer and look for a good upper end. Buying parts is going to be expensive if you want good one's, regardless of maker, and you will have more into the gun by far then a good lightly used one from a reputable maker.
I bought a Colt 1991 very, VERY lightly used for $400 bucks, and a NIB Commander for $500 from Cabalas last year, so decent prices are out there if you look. Don't start out with someone's unknown possible screwup if you are new to the 1911. It will sour you forever on the 1911design for the wrong reason.
Oh, and any decent smith or gunshop owner should be able to tell in about .5 seconds if it's a series 80, if he can't tell for sure I wouldn't buy it at all as he either knows jack about the 1911 or it's been totally screwed up.