As far as the grip panels for the Colt, be prepared for a lot of rooting through dingy cardboard boxes at gunshows and out of the way shops or pay the premium from online vendors that rooted them out and knew what they found.
The Tyler T-grip may still be available through the Tyler company.
As of a year or two ago I went through this process looking for a trigger shoe for my Stevens 416.
My online search eventually found the Tyler company and I noted that they do still offer the grips, although maybe not the ones you need.
Be forewarned, the current products (and prices) are not what they were but are usable.