Vintage 90s Ampeg 4x12 Ohm question:

[MikeGamm34]

Hey Guys,
I found a nice, older, Ampeg 4x12 and am having issues with the ohm situation. I have a pic attached. The 16ohm and 4/8ohm indicator is a bit confusing. There is a block that goes left and right and I am not sure which it indicates (whether the open spot is the indicator, or if the block indicates which ohm setting it is on). Right now, in this pic, the 'block' is on the left side, indicating 16ohm?! Please let me know what the picture attached represents. I need it to be on 16ohm, but don't want to risk ruining my amp. I can't find much info on these older Ampegs, let alone manuals. Thanks for any help guys!

https://www.flickr.com/photos/mikegamm/31126477381

[Hangman]

Ok, so the switch only changes the Mono setting. The switch slides left to right, when the switch is to the left it is in 16ohm mono mode, when the switch is to the right it is in 4 ohm mono mode. that should clear up your question about the block or open spot.
you can always double check with a digital multimeter if you want to be extra careful