Your assessment re the glued on sparkles, etc. is correct, but I never had much of a problem with them flaking off. There were two types that I remember, Remo Sparkltone and Rogers offered Colorflake. I am betting all Remo and just labeled differently. I remember seeing the Rogers Colorflake in their ‘68 catalogue and had them on a kit I played around that time.
They were a thicker film and may have a couple different film thicknesses as they offered a marching head. I have a few that I still use on front heads for bass drums. They are a bit more “dead” sounding, depending on the weights.
I attached some photos for you including on Rogers bass drums from 18”-22”.
BTW, I have several in assorted colors for snares and toms that I do not use, unplayed, and would sell the lot for a reasonable offer if anyone is interested.
I am also looking for an 18” or 22” bass head in blue sparkle if anyone knows of one.