Savage "hammer" spurs...

Self-loading pistols of any type were still far from mainstream when Savage put the finishing touches on their Model 1907, and despite the weapon being striker-fired, an external cocking spur was added, which allowed the weapon to be de-cocked like a conventional auto. The spur had the added feature of blocking the sights when the hammer was at rest, which made for a handy visual reminder that the pistol was either uncocked or empty (there being no last-round hold-open feature.)

Savage couldn't resist tinkering with the design, however, and the constant changes probably combined with massive overproduction in the first couple years to eventually doom the pistol on the market.

The second pistol from the left is a Model 1915, introduced as a response to Colt's wildly popular 1903 "Pocket Hammerless". One can only imagine that meeting at Savage headquarters:

"These people keep buying Colts!"

"They like it because it's hammerless and Colt's advertises that it won't snag on coat pockets."

"But it has a hammer! It's just internal! Our pistol really is hammerless!"

"But people see the spur and think it has a hammer..."

Thus the 1915, which eliminated the external spur, blanking off the slot in the breechblock, as well as adding a grip safety and a last-round hold-open feature. Unfortunately, the pistol was more expensive to make, sold at lower profit margins for the company, was trickier to disassemble, and the last round hold-open feature was fragile and breakage-prone. Tooling up for Great War arms contracts put paid to the 1915 variant after less than two full years of production, making it the rarest of the little Savage variants.

Lastly, the pistol on the far right has the spur-type hammer that was always available as an option, but became standard on the final variants of the 1907 and was continued on the Model 1917.