Does anyone know what the support is like for earlier model pistols?  I've got a line on a Mk VII for a good price, but I'm hesitant because I'm really not sure if replacement parts would be available or what swaps out between the two.  Speaking to a former Desert Eagle owner, he said that the major difference is the gas piston between the I/VII and the XIX and that they are not comparable.  Is anything else comparable or could parts be obtained from the factory?

Thanks!

What caliber?  My Mk VII in 357 has required the following modifications... Recoil spring plate required removing the nub and some minor re-profiling.  The gas piston is no longer available (357 was different from 44 and 50) and I had to silver solder the piston to the front of the slide.  No idea on durability of this modification, as I've only got 2 mags through it for function testing.

It's a .44

There is good factory support for consumables (recoil & extractor parts and pieces), and extras like mags and other addons.  For other parts there is Numrich, but then nothing really breaks that I'm aware of.