Hi Folks, lots of LT2/3 pistons out there with the single ring and double rings. I think the LT3 should have the double ring with the MX version using a single ring but some on fleabay have it the other way around. Also, not seeing too many for sale which have the rings included and wondering if it's safe to buy the piston without and getting the rings from Partzilla or some other source. Any advice would be welcomed. I'll check with Enduro nut to see if he has any of these in stock as well.

Enduronut is the place I'd start! 

(Prefix of the part number is the model code and will tell you if MX or Enduro... 305 is Enduro and 335 is MX)

There are lots of eBay sellers who list pistons wrong. My favorite is a DT250 piston that also fits an RT360 lol. In this particular case you should be able to swap a regular LT enduro piston into a MX or vise versa. I have never tried this but i have heard of it and see no reason why not. If your like me and like things original i would suggest getting with enduronut for starters as you already figured out. No not me the other one! lol.
If he doesnt have what your looking for then id start going by the part numbers and the pictures uploaded on eBay or any other site selling them. Shouldnt be an issue ordering rings separate if none are included with the piston so long as your ordering the correct rings for that piston.