All Beocord 5000 type 49xx are identical when it comes to the drive mech.
The differences are mainly related to the mains voltage, the power plug type and perhaps a few other territory specific things. 

First thing would be to ask the seller for instructions.
If the seller cannot help you, he most likely never tried fitting them himself and wouldn't know how or if they work or not. 
But, to be honest, if you bought off Ebay you will most likely sit with some belts that look somewhat right but won't fit.
Or they are too large or - even worse - too tight.
It's quite sad, but that's the story told by the amount of Beocords coming in here with wrong belts.
The bronze bearings in the motor won't take too high sideways loads for very long and spare motors are not too plentyful.

I cannot provide instructions for parts I didn't sell. And that's a principle. If something goes wrong with the belts I could be blamed
for it - been there - but I can supply correct belts (own custom production to original specs - no asian standard belts!) and
I can include instructions with photos and english text.

A set with the rubber parts for the idler wheel and the reel tables is also available - though I haven't made any instructions for them since
they are in plain view when servicing the Beocord.

Martin

Hi Dillen,

I have started my Covid lockdown project of renovating my Beo 5000 system.  Most of my system seems to still be in working order but the belts (at least those I can  see in the Beocord 5000 Type 4922 are a black mush. After reading all the historic posts ( a big thank you to all those who made contributions) it seems like you are the expert to contact. Do you still supply the belts please?

I'm located in Oxford,UK what's the best way to get them.

Thanks, Robert.

Robert, you have email.

Martin