Yes all spares are available.
Hope you still have the original parts diagram. If you do it's easy as the part number and name are there for your local tackle dealer to order for you.
If it's the pin on the main shaft that the reel clips over to stop the spool from spinning then you will have to replace the whole shaft on RE, GTE, GTEB GTEC on XTEA you can buy the pin and o-ring separately
If it's the Oscillating pawl which is always the first to break on these reels then replace the whole pawl, worm gear and bushing. Either way the repair will cost you around R150.
Your alternative is to contact Rapala VMC and send your reel in for service and repair.