When scanned, this comes up as Bartman and Radioactive Man 1 ashcan. I think mine may be considered a Hero Premiere Edition or something else Hero related. It has “supplement to Hero Illistrated” in white on the front and the Hero logo on the back. I took pics of both.
There is a series of “Hero Premiere Edition” – but those stopped numbering with #11.
Wetworks was Hero Premiere Edition #11 and was inserted in Hero Illustrated #7 according to my notes.
H.I. #8 had Extreme Hero, H.I. #9 had Bravura Preview Issue and H.I. #10 had Axis Jam. If I recall, those are all full-size comics.
Then H.I. #11 had the Bartman you have. That’s back to an Ashcan size.
So you are correct that your copy was released in the same manner as the Hero Premiere Editions, but I don’t think it’s in the same run – it came a few months after they stopped numbering/labeling the backs with “Hero Premiere Edition #”
Of course, that was more than 30 years ago, and so it wouldn’t be the first time my notes were wrong. 
Feel free to leave a suggestion on how to add this to Core as user friendly as possible. Thank you in advance.
Is what’s inside not the same as the “Bartman and Radioactive Man” Ashcan we have in Core? I get that the cover looks different
I have no idea. I would guess that it probably is but I can’t say for sure. I just have this issue. It’s not under hero premiere or the ashcan version.
It’s the size of a standard ashcan. The exact same size as the hero premiere editions.