SilencerShop has given me pessimistic delivery expectations on several occasions when the inventory became available within two or three weeks. I think the delivery dates are truly out of their control and they're trying to set expectations accordingly; but for common items, they might be a bit too pessimistic. Neither of the YHM devices that you mentioned are particularly exotic. I'd cross my fingers and check the web site a couple times a week.
Your alternative might be to look on GunBroker in the NFA section for Texas dealers selling what you want.
NRA Endowment & DSC Lifer