I think that's a great way to purchase a used reg guaranteed to work without investing anymore money up-front, i.e., getting it inspected/overhauled. In addition, your LDS should have no issue servicing those regs going forward. You may want to ask them whether they might cut you a deal on reg overhaul parts in the future, since you'd have to pay for those out-of-pocket (only customers buying a new reg from an authorized dealer are eligible to participate in the free-parts-for-life programs, when available).
Rental regs get used pretty hard, but the LDS will typically overhaul them every few months. Then, after a season or two, the shop will usually sell them off. You can be fairly certain that the reg model is a robust one (easy to service, not prone to breaking, resistant to freeflow, remains in tune, etc.).