Its only my guess that its been refinished once. Where you found that
date under the grips, look for something like [R], or [B], or <R>, or
perhaps [R-B]. Those are some of the markings for a refinish. Check all
around both sides of the grip frame.

Unless there is some good reason, refinishing always has a detrimental
effect on the collector value of the gun, because then the gun has
zero percent original finish; its been refinished. In the case of this gun,
the factory will not work on it , because its too old. They no longer have
parts for these old guns; any gun that comes in for any servicing is
always checked to make sure it functions properly. Since they have
no parts, they can't fix anything if it needed it, and therefore their
policy is to not accept guns this old, for any servicing.

The problem with refinishing is that the original roll markings often
get washed out, or even are lost. This is because a good refinish
requires a near-perfect surface. Any dings, dents, scratches, rust pits,
etc, have to be removed by filing and sanding, and this is what
damages the roll markings.

Bottom line is - unless there is some good reason to have a gun
refinished , do not do it.

Mike Priwer