I couldn't provide absolute verification that 62s were available from the factory with 261/3spd/OD. I saw the pickup the engine came from and it was a 1962. Also NAPA parts books make reference to that engine being available though some mistakenly call it a V6 while others correctly identify it as an inline 6. The engine had 12V coil, starter and generator. Also check
http://en.wikipedia.org/wiki/Chevrolet_C/K for their reference that the 261 straight six at 150 hp was available in the 1962 pickup. Finally I remember reading that the light green color of the bellhousing was correct for 261 truck engines of that year. Being a newbie its highly possible I may not be absolutely correct. If not I'm sure more experienced members will correct this post.
Jerry.