I may be able to get pics...
But it may take a few days. I have only seen his picture of this gun, and I think I can get the file from him to post, but it may take a while.
The gun apparently belonged to his wife's uncle, and her father kept it for a couple decades after the uncle was killed in a car wreck, and only recently gave it to my friend's wife. The gun has apparently home made wooden grips, not the original ones. He has not (yet) fired it.
Along with posting here, I was doing a bit of google searching about the gun, and did find one site which listed approximate values, although sadly, I cannot remember which one that was. Sorry. It listed the Mann .25 auto with values ranging from $100 to $395 (I think) for a perfect specimen.
The problem with the "blue books" and other listings is that they are, like the pirates say "Arrr, not rules, but more lioke guidelines, ya might say".
A dealer will look in the book, and offer no more than he has to, but may be able to sell a gun for much more, IF it is demand locally, and thanks to the Internet, local now covers a lot more area than it used to. Pocket pistols are collected by a few people, but not near as many as collect other guns. If you know a collector, they might be very willing to pay a premium over "book" price to get a rare specimen, while on the other side of the coin, someone just looking for a gun might not be willing to pay "book price" for an old .25 auto, and it might sit unsold in a dealers case for a long time at book price.
Back in the mid 70s, a S&W M29 .44mag would sell, and sell fast for $400 when the MSRP was $283.50, because the factory was two years behind on orders, and demand was high. Look at the jump in Winchesters (even newer ones) when the New Haven plant closed, and it looked like there would never be any more made. The market is ....funny sometimes.
A lot (not all, but a lot) of the pre WWII European pocket pistols have exquisite machine work, some of them being fully polished internally even. But they do not usually bring a lot of money on the market.
I will try to get a picture. The owner has no desire to sell, as it has sentimental value to the family.
All else being equal (and it almost never is) bigger bullets tend to work better.