Does the sear have a serial number on it? It is my understanding that because of some problems with changing information on the forms, the NFA Branch is checking previous forms compared to the form submitted. This sounds like a nightmare transfer and could get this transferable thrown out of the registry.
Personally, I would never buy a RR with an unaltered semi automatic receiver and a unregistered sear. Which begs the question, was someone trying to alter the paperwork to make an unregistered HTA sear into a transferable? Or back in the day when registered sears were cheap, did some "repair" a HTA machine gun with a transferable sear because the unregistered sear or pack with the unregistered sear would lost or destroyed?
The HTA gun was registered as a RR. If a transferable sear was "married" to the receiver, this might be a loophole to have the semiautomatic shelf removed and the front push pin installed. My understanding is that the FATD ruled that manufacturers and private individuals could not destroy the unregistered sear and install a push pin as drilling the hole makes the receiver a machinegun, but the unregistered sear has been ruled to be a machinegun. So that would be two items that are ruled to be a machinegun with only one registration. Because the registration states that the receiver is the registered part, as a collection of parts, if the unregistered sear is destroyed first, then the receiver being a semiautomatic, there is no functional machinegun. So in modifying a semiautomatic receiver with an unregistered sear, there would either be two machines or no machineguns according to the FATD. Of course the FATD might consider a registered sear "married" to the receiver to make the receiver an unregistered SBR because there is not enough room to use two auto sears.
To me this is a nightmare. If there is a registered sear market value is around 30,000 with some HK parts. At best, the HTA receiver gets modified, divorce the sear and have two HK machineguns. It all sounds like lawyers and problems.
Scott
ETA "Tranny" is the cool kids way of saying transferable.