Depending on when the handgun was made (pre-2003 I believe) a bore lock would not be required. If you can prove the handgun was made pre 2003, I believe all you need is a cable lock.
If you do need the bore lock, I would call other ffl's that are in your driving range and see if they have any that would work that are for sale. I'm sure for them, a sale is a sale.
Smokescreen is correct. Handguns made after 2002 need bore locks. Those made earlier do not. They do however require a lock (cable lock). It is spelled out on the 77 R.