As Geoff observed, it was reproved in 89' under the 1954-1989 Rules. 3 Tons is for a max. service pressure of about 9000 psi
Original bores were 13/1 = .719" to .728". At reproof R .728" and L .732" so likely not much honing.
Are the chambers still 2 1/2"?
The only downside is one has to use specialized shells in it that won't be available in the boonies. County Walmarts tend to have more robust inventories than those in cities so one might find extra light target loads, however, shot size will be US 7.5 or smaller.
