The grips are definitely not factory, but as above said...they are old time full rubbers, probably put on by original owner to make the gun easier on the hands. They may have been a dealer install at time of purchase.
The felt recoil from full load 44 maggies can be very uncomfortable for some shooters, and the original factory checkered walnut grips just add the abrasion of the palm under full recoil and torque.
As the above post, they are probably old time Pachmeyers, but check on the butt of the grips. I have a very old pair that also look just like yours, however the butts has a rectangular embossed logo section that identifies the grip as "Imperial grip" and the company is Mershon Company of Los Angeles CA, USA".
Mershon was the predecessor company that Pachmeyer bought out way back when. The grips are worth good bucks to collectors and shooters alike so don't lose them.
Another hint is to definitely take those grips off and check underneath for evidence of rust or past moisture retention. Any rubber grips will hold moisture against the metal and eventually cause some rust, so just beware especially when those grips may have been on the gun for a long time.
I love my Model 29, great gun, great shooter, good looking and if the Maggies take their toll on your hands (or wrist) just drop in some 44 Special cowboy loads and keep on shooting.
Either way you got a great gun in what appears to be very good condition....so load er up, shoot some groups and give us a range report.
