did sharp ever make speakers for the gf 777 767 range of boombox which plugged into the subwoofer, external speaker plugs in the back!!! I mean purpose made one's just for the 777 with the same style!!!????

Not that i know of. Every box has speaker output connectors but i guess that in case of the GF 767 -777 one has to fabricate a subwoofer to hook up on this output.
I don't know if you tried to connect a speaker to it.
Only lows are coming out in this case

Sharp may have made external or book case type speakers that match up tot he 777 not sure...but according to the owners manual...they dont specify a model you can..but states that it can power external speakers...the requirements are 4 to 8 ohms with a 3.5mm connector...and that the connections made in the connector must phase the speakers correctly...hope that helps...

I'm not intending to put any speakers on the old girl!!! but just wondered if they were ever available!! I must say I haven't ever come across speaker with a 3.5mm jack !!!

No, I don't think they did. Just the outlets to pug in any brand at the spec they give.

Sharp marketed a range of speakers sold on their own for connecting to boomboxes, but nothing specifically for the GF767/777, AFAIK.
Here's a couple of pages from an old Japanese Sharp catalogue, one showing the speakers they sold:

& another with pics where the boomer is the centre of a home audio setup, with a turntable & speakers added:

"System Up"

thanks for that 3D woofer man

wow thats very nice ISO...i like the stand and handbag for the box...so cool...thanks allot for sharing...