I saw a V. Bernardelli Italia SxS hammer gun on the shelf at a local gun shop. 25” barrel, straight shock. Silver frame with very nice engraving. Tight lockup with the top lever right of center. Estimated 85-90% condition. Curious to know its estimated value.

I don't believe that gun was made with 25 inch barrels.

It might have been 26”.

I sold a Brescia, which is the plainer version with less engraving for around $1,000, as I recall. I probably sold it a bit too cheap, but I actually wanted to sell it rather than admiring a price tag.

My GUESS is that an Italia could bring $1,800-$2,400. Of course, less if the seller is willing to take less.

The V. Bernardelli seem to be about the sweet spot for high quality yet reasonably affordable modern hammer guns (with good steel, 2-3/4 chambers, etc.). They're nice guns. They're light, though.

And yeah, I don't think their 26 inch barrels were actually 26". Probably closer to 25".

Brescia was sold with 28 and 30 inch barrels.
Italia had 30 inch barrels according to the old Gun Digests. The Digests may not be the complete story.
Custom barrel length could be ordered.
I would examine the muzzles and chokes very carefully.
My Brescia, which I bought new in the late 60s, came with 28 inch barrels.

There is also an upgraded Italia Extra model. My 7 yr old Bluebook indicates the V. Bernardelli values are only listed on the online edition of the Blue Book

What year was that catalog published?

It's from a 1968 Shooter's Bible.

The following numbers are stamped on the underside of the barrels and the frame flat: 653xx that I assume is the serial number. The number 1173 is stamped on the barrels, frame and inside surface of the trigger guard. Could that be the date the gun was made?

Italian guns have a date code of Roman numerals, an later dates a two letter code - you can easily find the Italian date code table by searching on Google.
A useful site for proofmarks is shotguns.se - a Swedish enthusiast's site.

There is XXV stamped on the barrel flat. There is also 15.9 stamped on the underside of each barrel. Also XX on the left barrel and XXXX on the right barrel.

I measure the chokes as .010 for the right barrel (Lt. Mod) and .030" (Full) for the left barrel with my Skeets Bore Gauge.

It appears that that gun is chambered for 3" shells. Using a piece of stiff plastic as a gauge, the chambers are about 0.1" longer to the forcing cones that my 20 ga. Ithaca SKB that is chambered for 3" shells

XXV is 1969.
15.9 is bore diameter in millimeters
The weight of the barrels at proof, in grams, will so be stamped on the underside

For the record, the gun I sold was a 12 gauge. I would think a 20 would bring quite a bit more.

Thank you for the information. 1173 is stamped on the bottom of the barrels. The barrels on my gun weigh 1150 grams using my digital kitchen scale that may not be that accurate.

Curious why they would mark the weight of the barrels on the gun.

Barrel weight allows a buyer to know if barrels are altered significantly from the condition when they were proofed.