It isn't that the 1157 socket isn't approved, but the 1157/56 replacement bulbs
aren't approved by the US DOT or any other body in automotive use. One reason you might find these LEDs are "unfocused" is because that is intentional in this application. These are designed to be an even 360-degreee illumination, emulating a tungsten taillight bulb.
Personally I wouldn't worry too much about resoldering LEDs. The bulbs that use dozens of 'em usually use cheap
[read: affordable] noname LEDs, expecting some will burn out but enough will keep working. That's valid logic for many things.
But any prime LED should last 50,000 hours till 70% brightness, and 100,000 hours overall. 50,000 hours at 12 hours per night every night is only 11.4 years, surely you'd want to go inspect or replace something by then? Or, wait 22.8 years for the damned thing to die?(G)