When the 4-bbl was installed on my 318 (about 5 years/3,000 miles ago) the original timing chain and gears were replaced with a SUM-G6603 double roller chain/gears. I also had a new water pump (Cardone 8-vane) installed.
The engine is going in to be rebuilt in a few weeks. Can these components be re-used on the new rebuild?
3000 miles? Hardly used, still new IMO. Clean it, inspect it and run them. Slap a MP chain tensioner on with the timing chain if you want to spend any more money on stuff.