As a table mechanic I see tables everyday. Then sadly I go shoot at a pool hall at night. But there are some signs to look for.
First off make sure it isn't a 1peice slate. 1 way to check is to feel underneath the bumper on the slate and you should feel 2 holes close together somewhere between the 2nd diamond and the 3rd. Sometimes for some reason mechanics fill those in so look under the table too. If you see wedges in the middle of the table it is a 3peice. And if the slate hangs over the frame you'll see the gaps.
Also make sure it is backed slate. Or has wood backing. If it was less than $1,000 it wouldn't be as big of a deal. But for that money you can find better. But being in Puerto Rico I understand your plight. But by looking under the table you should be able to tell.
If the cloth is in decent condition I would keep the cloth. A good mechanic can take the cloth off and put it back on just as you see it there.
The table to me looks like a cross between a Diamond (with the legs), Gandy (rails, blinds, ball return), and a Valley coin-op (With the textured corner/side pies and corner covers.
Also make sure the slate isn't cracked. You can say that your not going to pay him immediately but will schedule the appointment at a time both you and the owner can meet there and watch it taken apart. And state that you will buy it as long as the mechanic (Your paying) is there. If it is damaged pay the mechanics for say a Knock down (Or a little less) and take your money elsewhere.
Hope that helps.
