I come late to this discussion unfortunately. I think if the OP spent $1300 for a clean well taken care of M52-1 he did okay. I have owned any number of M52's in all configurations, but the only ones for $800 or less I have seen are dogs in looks or function. If you want a super nice one with original box and all be prepared to spend at least $1500 and up. At one time I had 5 or 6 M52 variants and I now have 2 left. One has a new Clark barrel and bushing in it and it not only shoots very well, but it cleans up much easier that any OEM barreled M52 I ever owned. Clark still sells barrels and bushings, but their stock on these is getting low and word has it from the horses mouth they will not be making anymore. In other words, making these isn't worth their time and effort. The market for these items is much shallower than they anticipated.
Depending on how the soon to be released "new" magazines work there may be a price drop on originals, but OEM magazines will always be expensive and desired at this point. I have a mix of OEM metal follower magazines and plastic and have never had a problem with either. Just another old wives tale as far as I am concerned.
The hay-day for M52's has long past and much more accurate pistols have come on the market, but for much more money too. Even ammunition has become difficult to find for a M52 and who would have ever thought 148 grain lead wadcutter ammunition would be hard to find!! I load my own so it is of no consequence to me.
The rub on a M52 is in finding parts for them and someone who knows how to work on them. As far back as I can remember people always complained about the early long extractors on the early M52. I obtained a spare extractor for the one I owned, but never had to use it. It was nice piece of mind knowing I had one though. The same complaints were voiced on the early M39's too so take it for what it's worth. At one time I used to closely watch Gun Parts Corporation's website for newly arrived M52 parts. If they had something I thought I might need I bought it and put it in my M52 spare parts box. I now have a bunch of spare parts that I rarely ever need especially being down to only 2 remaining M52 pistols.
While not a terribly fragile pistol by any means, the two quirks of the M52 were the shooter and the ammunition used. The M52 was best used by experienced shooters as it was not a forgiving pistol. If you made any mistakes shooting it the pistol would let you know immediately. And if you used ammunition it did not like it also let you know that immediately. However, shooting a M52 of any variant was a reward in quality now long gone. If you didn't keep it clean and/or treated it roughly you were most certainly going to have problems and DO NOT drop the magazines on a hard surface. Many M52 shooters blamed the gun for these problems when they were actually the fault. I can only think of one or two other factory built pistols in my lifetime of shooting that were as well made as a M52 and were as much fun to own and shoot. It's still a darn fine pistol the likes of which will never again exit the doors of Smith and Wesson.
Rick H.