I doubt a table mechanic will be able to convert at GC7 to drop pocket except by blocking the ball return track.
The molding of the pocket is very specific to the GC7. No one else will have that unless they make an injection mold at considerable expense. It's not like GC1-6 where both options were OEM, and the mechanic can just swap them afterwards in either direction if he had the correct parts. Now, if Brunswick does release drop pockets in the future, swapping them at that time would probably be easy.
Blocking the track would work, but how many balls would it hold in that case? Probably not nearly as many as a true drop pocket would, because they usually have a deeper bucket area to hold the balls.
I suppose with 3D printing these days, someone could cut the bottom of the existing pocket and add a 3D printed bucket to it. I just don't see anyone hacking up their 13k USD table to do that.