This courtesy of Bruce Day on the Parker Gun Collectors Association site back in 2012 --

Here are the three Invincible Grade Parkers, which are fully owned by the NRA. While at one time they were held by the NRA as trustee, they are now owned. Two are straight hand grip, one is half pistol grip with a foliate or leaf carving.

[Linked Image from i.imgur.com]

So, I guess they will not be part of the Petersen estate monetization.