The 43's are my choice if you are going to buy one. My initial impression of the gun is good, as the patina match on the parts matches very nice (for this type of gun). Do the serial numbers match on all the parts? If so, jump on it.
If they don't, it's still a good looking gun, but remember that many collectors have issues with the overall appearance of these late war guns as they tend to be (compared to MP 38/40 etc) in much more, shall we say, field used condition. I guess mostly it's the cheaper late war production that allows mother nature to do her thing. Also, compared to most other SMGs this particular gun seems to have a very narrow niche of collector interest. I can't tell you why, as the gun certainly fills a WW2 collector's bucket list. I for one almost bought one in similar condition a few years ago but ended up passing. Not sure if I regret it or not, but looking at this one makes me wonder.
In any case, the price looks very nice (mine was priced at $35K w/matching SN). Heck, what else are you going to spend you money on!