Ben,
Depending on your location, some iof us can point you to a good gunsmith who might be willing machining a custom base mount. Many manucturers make stock bars, including Leupold and Weaver. I had some made with Picattiny rails for multiple sights mounting.
Regarding your action, to me it's definitively a reworked action, as the S/N seems to have been milled out and re-stamped. As said before, the cocking piece and bolt handle are also a good indicator of a Target purpose-made rifle.
The "S" on the barrel means it's made for the 140 grains spitzed bullet (M/41). I wouldn't bet too much on the fact that this barrel wasn't match selected.
J.V. is the correct inspector stamp for a 1905 receiver (M96) but the serial wadefinitely changed to reflect a modified action (or, if you'd like a Target built rifle).
Is the stock glass bedded?
As a hint, to take close-up picture, take the macro option of you camera, it will make it clearer.