I have read those claw mounts are generally very poor, as the iron claws are subject to wear and loosen under recoil. Probably be OK if you mounted it and didn't dismount it.
Please don't do one of those Weaver butcher jobs or try to have the bases removed. Claw mounts are very, very dependable if done correctly, and will easily last your lifetime with perfect reliability. Trying to remove the bases will likely destroy the value of the gun for the sort of folks who collect and use them (me for instance!:-) ). Call J.J. Perodeau at Champlin Arms in Enid, OK
http://www.champlinarms.com/Default.aspx?tabid=37 . JJ is an expert on combination guns and can build you a set of rings (one inch or 30mm) to fit those precise bases. He has done several drillings and cape guns for me over the years and recently built a complete set for my .375 double. I have probably put 300 rounds through the .375 over the last couple of years, taking it on and off at range sessions and it is remains as tight as the day it was built. Like the action of a good double, the secret is in the fitting. Shot a big buff in the Caprivi with a bolt gun last year, but the double will go with me next time. JJ is the only guy I would trust to do this sort of work on a DG rifle. Anyway, give him a call, tell him what you have and he will gladly walk you through the options. I won't be cheap, but neither is that drilling.