No mechanic on the planet is paying 3k for a set of slates. He was pulling your leg or didn't know what the hell he was talking about.
Your table is super nice! I think if you market it you could get 2-3k because it's so pretty. The only downside I see is when a ball hops off the table and hits the rail top, what will happen?
Pool tables are very hard to move. Players like us on this board are your target customer. We want either commercial Gold Crowns, or commercial Diamond. A lot of people here have modified their GC's to spruce up the appearance. I've yet to see anyone paint the top though, so that's the only hold up on this table. Painting the sides as nice as yours are, and plating the castings, increases the appeal and value, IMO.
Homeowers that are not players want furniture tables.
Plus, you are competing with free to $300 furniture tables available all day long on Craigslist from people that simply want them out of the house so they can have their space back.
Also for context, an original, unmodified GC 1-3 is worth about $1500.