That has unfortunately always been a weak point on Maruis (and other plastic slide pistols): often time green gas is too powerful for it and will end up causing damage.
I don't think it warped/deformed the slide (i doubt plastic/abs would deform like that unless it melted), but there may be some damage developing. Or something may be misaligned.
Slides aren't a restricted part, but make sure it is the slide and not some other part (unless you plan on getting a complete slide). And beware ordering from Evike if that's where you were looking. The WE is supposed to be a clone of the TM so parts should work.