They do look short but... Looks similar to some of the SCARs that Clyde Armory was selling as trade-ins... They described them as "featuring a "13.5" barrel with a 3.5" pinned and welded flash hider, making them non-NFA weapons." See attached
To echo what Dawg said - if the overall length of the barrel (which includes any permanently attached muzzle devices) is 16" (or greater) then it's not an SBR. If the brake is pinned / welded it looks like its 16" oal. But obviously would make sure before buying.
as Dawg said there were a number of scar17s released to the secondary market in this exact configuration via a LE trade in.