That is a reasonable price. If the service was done by someone who knows what he is doing that will go on for years. The old seals tend to harden and break up. One assumes as it was only three years ago he used modern seals.
You will need to get something like a Feinwerkbau 102/103 to get better accuracy, even then it is debatable which is better. It will be at least as accurate as a Gamo Compact or HW75, probably better, if you get on with it.
Before you dismiss the plastic grip you need to try one. If it fits you it is a very good grip, the moulding is very well done and the 'stippling' pattern is very 'grippy', it just depends on the shape of your hand.
I have stripped mine twice now and have had no problems. There are guides about on the internet, however, if the service was a good one three years ago you won't need to worry about servicing for quite a while.