Hi
In the boot under the carpet there should be a sticker with the model number and somewhere there should list the engine code! as Rub jonny said i bet its a PB.
smoking could either be the Oil stem seals or the piston rings. Might be worth doing a compression test to see how good ya rings are. Oil stem seals are easy and cheap enough to do. The rings are usually brough from main dealer and are expensive for what they are. I recon the Oil stem seals would do the trick, worked on mine.
If its old, i'd suggested giving the engine a good flush out, treat her to come new oil and filter. Might as well do this when u do the oil stem seals. With one of my early mk2's the oil light used to come on loads, i flushed the coolent and treated her to some nice clean water and it sorted the problem. Your probably need to get a hose in there if it hasnt been done for a while, thats what i had to do, the coolant was like rusty water.
If you are a capable DIY mechanic most things can be done reletively cheaply on a golf.