I don't think I've ever seen a Gold Top BLS-59. I think they came mostly in the regular burst finishes as well as some with an oil finish. It might also be a BLS-95 in that regard. With luck it's a BLS-120. The BLS-59 was the top model of the Vintage Series range while the BLS-95 would be the lowest. I'd love to get my hands on a BLS-59 myself as they generally held in high regard. I'm certainly no authority on the Bacchus Les Pauls (you should check out the forums at MyLesPaul .com for that, they have a LOT of knowledge on MIJ Les Pauls over there) but I think the used market price for a BLS-95 would be around $600 while a good BLS-59 is closer to $1200.
The main difference would be polyurethane finish (BLS-95) or nitro lacquer (BLS-59). There is probably some difference in the quality of the materials and electronics too. The specs on the BLS-59 varied a bit (it was essentially a handmade instrument after all) and some were made with premium materials like Honduran Mahogany and Brazilian Rosewood etc. Those are very rare and likely to go for a lot higher prices. Easy way to spot a BLS-120 would be the headstock. The "open book" indent - or what the hell you call it (the "V" notch on the headstock) - is softer on the BLS-120 models while the BLS-95 and BLS-59 look exactly like a Gibson headstock.