Johnny Mac must have had a licensing agreement with Dunlop where he acquiesced to a blanket endorsement of their entire product line without itemized royalty for the use of his name and likeness. It's almost like co-branding. Can't think of anyone else who has done something like that since.
I assume "Volkl head shape" means egg-shaped? If so, your "McEnroe Comp" must look more like the 1983 "XLT" than the example below (an early one with individual grommets), meaning Dunlop recycled the same name for different models:
Of the half a dozen of so GW-sourced Taiwanese "McEnroe" models I tried out over the years, I was most impressed by a beat-up "McEnroe SL", which played like a slightly larger, lighter, stiffer, and more dampened version of the pristine "McEnroe Comp" above, with subtle PWS-like swells on the
outside of the frame that helped to put the sweet spot in just the right place (for me). In this specific case, having "McEnroe" in the name might have been detrimental, as potential buyers likely had no idea how different this racquet behaved relative to other department store McEnroes. Perhaps Dunlop itself too, had no idea how different their countless McEnroe models were, and probably didn't care.