I guess really it all comes down to where you live as to what your likely to encounter.... your profile says "South Pacific", do I take it to be around 42 Below? Well then in New Zealandyou will find quite a few original MP43/MP44/StG44 rifles as they were imported into New Zealand back in the late 80's, the majority were converted to MSSA's with some Cat 'C' (full auto) versions too. I believe the rifles came out of East Germany
and a lot of them were refinished. if your lucky you will get an original WW2 magazines if not it will be one of the later East German produced magazines.
What you will need is photo's, lots and lots of photos of all the markings and believe me the rifles are covered in markings. Do not expect to find a rifle that is made by one maker, the rifles were assembled from part bins and you can have a dozen different makers markings on the same rifle with matching serial numbers. Without this info no-one will be able to help guide you.
I use to have one.