This action never really looked right to me for some reason.
For a top lever hammer, I prefer island back action locks such as on the Rodda at Vintage Doubles

http://www.vintagedoubles.com/inventory....mages/990_1.jpg

Way less money to boot...but, as stated above, not a 577 although they also have a Lyon & Lyon in 577BPE as well.

Also, the shell in the case at Cabela's looks like a 3 incher. Makes me wonder if the chambers are unaltered. Could be there just for effect.