By joining you will help ensure that we can continue to provide this service
I have the same carbs on my R60/7. They do go up flush. I would think that yours should too.
I don't know what the carb bowls looked like or the inside of the carbs looked like when you started to resurrect the bike.
If the gas was left in the carbs to age, they may have varnish in some of the internal passages. Depending on if this is the case and how bad the varnish, you may get by with just a minor bit of disassembly and squirts with carb cleaner. The worst case would be a total disassembly and soak in carb cleaner or ultrasonic cleaner.
IF it were me, I would adjust the floats, and run it for a bit hoping fresh gas would perhaps clean out things. If that didn't help, I would take them off the bike and as said do some careful one at time disassembly with carb cleaner squirting.
If you get them apart and they are really plugged up, then, a soaking in a gallon of carb cleaner or ultrasonic cleaner will be be needed. I really don't think you will need to go this far.
Good luck, St.