Thanks guys! I'm afraid I'm just barely scraping by on a Social Security disability pension, so I don't have a digital camera capable of a close up of the plug. But I can tell you that it's a Radio Shack product number 274-0284:
1/8" Stereo Phone Plug (2-Pack) - RadioShack.com
Considering that one of you said the tip is the right channel and the diagram included by the other of you shows the tip as the left channel, I'm concluding that it's a toss up and it probably won't really matter which of the colored wires I solder to which contact.
I found a web page that says that the red wire is
"usually" the right channel which further reinforces my conclusion that based on the information I have in front of me, there's no way for me to know for sure which wire should go to which contact.
From visual examination it looks like one of the contacts runs down through the center of the plug, but I have no way of telling where it comes out, since I don't have a multimeter (I'm 66 years old and have wanted one of those since I was a teenager, but never got around to buying one).
Anyway, I'm just going to make a guess. I can't imagine it's really going to make much difference to me. I mean, how often does it matter whether the left signal actually comes out of the left speaker, right?
Thanks for responding to my query. I'm sure I'll be back again soon with another problem.