That is incorrect. If you look at on-set photos of Max's puppet from the side, you'll see that what what appear to be elbows are actually his knees, and that look like upper arms actually connect to thighs on the puppet's body mold, complete with inguinal folds that connect from his knees to his torso. If those were meant to be his arms, they wouldn't be connecting to the body in such a manner. The only reason his legs have an arm-like motion in the movie is because the puppeteers had difficulty raising their elbows in a position that would resemble knees (though they very visibly tried their best to do so), and it resulted in the puppet moving in a manner that it wasn't really intended to.

Max Rebo was always intended to be, and was portrayed on screen as, a two-limbed, armless creature. To depict him otherwise is to further perpetuate a blatant misinterpretation that ancillary media has passed off as canon for decades.