Totally aware that he was a vintage concept, but because 200x fleshed him out and the figure is based on that appearance, I consider him 200x.
The same distinction applies to Evilseed and Marzo for me- I recognize that they were created in Filmation- but because their figures will take on the 200x look, I consider them in the MOTUC line 200x figures. However, if say Evilseed were to come out in his Filmation look in MOTUC- to me he would be a Vintage character.
Marzo and Evilseed both arguable have 2 different interpretations. Keldor is different in the sense that Vintage came up with him- but never truly explored the character. Kinda like how Carnivus was introduced in MYP, but he might end up being more of a MOTUC character after all is said and done by MOTUC fleshing out his bio and place in the mythos.