I don't know if Heckert did make a plain satin glass Nick to be honest.
And actually on close inspection that lamp I linked to appears to have the minutely crazed iridescent finish not plain like yours.
The piece I have and the ones I've seen close up have a crazed minutely crackled iridescent finish suggesting the finish has been created in a different way to that on your lamp (which is really gorgeous btw
).
I think if I recall correctly they are Cypern and it may have been made by Josephinenhutte for them (don't quote me on that, I'd need to look up what I found out again - info is somewhere here on the site though)
So the cypern finish looks very different on close up inspection to my Loetz Olympia satin iridescent finish pieces for example. They are completely plain with no crackle and where it looks, close up, as though the satin iridescent finish has been 'brushed' on somehow. Different again to a Murano piece I have where the satin finish looks as though it's been done by dipping in acid or something.
Maybe yours is none of those and by a completely different maker not yet identified
It's certainly similar to the lamp shape you linked to and that's might be a decor that can be matched hopefully?