Many LBS's have upgraded shifters, etc, for customers, without swapping out the cable stops.
They may have a small ziploc bag lying around with a pair of those in it, including bolts.
Many times, the bag is green. I don't know why.

I picked up two sets that way. Though I know the LBS paid nothing for them,
I didn't blink and forked over the $10 for each set.
Not my business how they got 'em, so I paid and was glad of it.
If the shop had said $20, then I'd have gone elsewhere.