Looks like the usual ordinary alpha pot or similar (5kOhms, linear taper), those are available almost everywhere (and ie at Mouser, Digikey, etc). If you can salvage the mounting bracket (in case it is detachable) you're set, because those are a bit harder to get, possibly.
I replied to your other post - it should be a dual 10K pot if you believe the Hafler schematic/parts list. Hafler p/n RV-0818 (which you might still be able to order from Hafler.com). The original part was mfg by ALPS and is p/n 344A-10KBx2.