IWC thoughts on repair to crown and stem with rep or gen parts

[glassreplica]

Hi there. I have a lovely IWC BP 5004, however, it has a couple of problems and I wanted to get some advice before I spend a fortune sorting them out.

firstly, there is a tiny mark - looks like a small grease mark on the dial (may or may not clean off) and also a small spec of dust is sometimes visible on the dial. I could probably get this cleaned out, but also thought whether it is worth upgrading to a gen dial - is this mod worth the cost and would it be visibly noticeable.

Secondly, the crown on my watch simply pulls out to wind the watch up, whereas I understand the gen unscrews first and then pulls out to wind. Am I right on this? Also the crow has also lost its spring to it and so it is hard to get the crown in to switch between winding the watch and changing the date. It would be ideal to replace the crown and stem with one which screwed in and worked better. Is it possible to get rep parts which do that? Or is it worth upgrading to gen parts?

Any thoughts would be really appreciated as this watch is a keeper and I would like to make it as accurate as possible as these little things do niggle. Searching through some of the posts makes the mod look easy for a watchsmith (one of those listed on rwg) to carry out, but i want to be sure.

Thanks in advance