It's my understanding it does, but I'm not 100% certain. I hope someone else chimes in with full confirmation ... I too am in the market for the Archer wingtip VOR antenna.
The SL30 only has 1 nav antenna input. Yes the GS and nav works on the SL30 with only one Archer VOR antenna. If you have one of the radios that requires a separate antenna for GS, you will need a splitter.
I just received an email from Bob Archer. He said the antenna does receive glide slope. Also the antennas are a lot less expensive if you purchase directly from him.
Aaron