GM-GMC: Replacing front turn signal on 91 Sonoma, auto parts stores, dash lights

Question
I already know that I can't replace dash lights that are out, but surely I should be able to replace a front turn signal bulb. I can't seem to figure out how you get to it. Thanks for your help.

Answer
I do not own anything that new, but I will try to offer possible solutions:

There must not be any screws holding the lens on from outside the vehicle, for that would be the most obvious way.
The bulb holder likely twists into the turn signal assembly from the back side of it.  You may have to remove the battery if the turn signal is mounted in front of it.  Otherwise, it may have some other item, such as a coolant overflow tank, blocking access.  In some cases, the access point is from underneath and may require removal of the fender liner.
If all else fails, some auto parts stores have salespeople who know how to change bulbs.