The slave cylinder looks normal and if the clutch push rod is not wet with oil I’d say everything looks fine. I would certainly recommend drilling a weep hole in the cavity (see online forums) to let fluid drain out should the slave develop a leak later on.
I’ve replaced two slave cylinders on older bikes that use brake fluid in them – one was still working fine and I replaced it as preemptive maintenance, and the other was completely gone with all the fluid drained out and into the clutch. A weep hole would have prevented this.
You can get new slave cylinders at Beemer Boneyard for just over $100, and you might want to replace it for peace of mind.