Just received this Sat from ebay. This was listed as a "Mac ADB Keyboard" but after getting the seller to post a pic of the connector's pins, I figured this was a Tandy 1000 version. After I plugged it into my 1000A, I was able to confirm it is a Tandy 1000 version. I'm not sure why this is marked as a "PC-Jr" version. This might be a "Frankenstein" version, someone obviously opened this up before. I think the switches are to swap the CTRL & CAPS LOCK keys, etc. Unfortunately, I got rid of the one I bought back in the day when I sold my 1000TX.
Tom