587 heads

If they’re 1.88 now, they always were.

You can go from 1.88 > 2.02.

From 2.02 > 1.88...... not so much.

From what I can tell, it looks like they have the factory valve seats/valve job.

Depending on what condition the guides are in, and what your intentions for the heads are...... it could be fairly cheap to get them into serviceable condition...... or it could get expensive pretty quick.

Edit: Just looked again.....they have replacement guides in them now.
If they’re sized correctly(or at least, not too big now)..... that’ll save you some $$.

Edit 2: did you mean the heads came to you with 2.02 valves, but have not been cut for them yet?
If so....... there will need to be more porting done after the seats are cut for the bigger valves.
Porting comment: the exhaust ports have more work done to them than would be necessary for the amount of work done to the intake ports.