I've had a Mark I in .357.  I've had a Mark VII in .44 Mag and a a Mark VII in .50AE.  This is my first XIX and first with the ported barrel.  

I traded an Arsenal SAM7R for it, and also got 2, 20rd boxes of Hornady .50AE and one box of 50rds Cor-bon .44 Magnum (240gr).  Has OEM and Hogue grips along with aftermarket fiber optic sights (on both barrels) - but also included the OEM sights.  Also has all the little tools that come with it.

Looks like it has a factory mag for the .44, and a ProMag (yuck!) for the 50 AE.  All the paperwork and CD were under the foam and the original buyer (whom I did not get it from) even has his name and info written into the back of the manual.  Looks like it was bought new in CA.  I'm surprised these are legal in CA.  I'm guessing that means it was bought as a .44Mag and he bought the .50AE barrel after.

The holster is a leather "MASC" - seems good quality, but admittedly, I would never consider carrying this; lol.

So...  I need to buy at least one OEM/Check-mate .50AE mag.  Seems like the best I can find on one is just over ~$50 shipped for one.  Is there some super-secret place to get good mags for this?

Nice pistol. One day I will buy one just because.

very nice acquisition, well done.

consider getting the IMB (Integral Muzzle Brake) 44 Mag barrel, really makes a difference.

congrats on your purchase.

Nice score.
Midway currently has the checkmate mags for $39.99. Cheapest I can find.
https://www.midwayusa.com/product/1006122961?pid=161729

Funny, my local gun store had its customer appreciation day yesterday and also had a sale on old stock. Had several boxes of old junk they could not sell.
I was digging around and found a brand new in the factory packing, 50AE mag. Sticker said $5 !!!!. I about crapped my pants and started digging like mad looking for more. Only found the 1.

Now there's a deal (on the $5 mag).

Thanks for the link; exactly what I was looking for.

Nice!
Always wanted to try a 357 or 44.

These are the only two calibers I would consider for practical purposes.

I really like the idea of having low recoil and longer range accuracy with DEs using Magnums.

Nice OP.  I opted for the 10" .50.  Makes a statement at the range for sure.