So long as you've also checked to make sure the coil's making a nice fat spark then yes -- the carbs could well be the issue. The diagnostic tree on these cars starts with the ignition first but I have seen poorly running B20 cars with fuel system problems...

The CD175 carbs are pretty nice carbs, in my opinion, at least if they're operating 100% correctly, and I get the impression that they've got such a bad reputation that people rarely bother to actually sort them out.

Because they're common on all sorts of british cars, I suspect there is still good support for them -- take them apart and replace anything obviously wrong (IE they should be identical between the 2 carbs so if the springs are different, replace them both, the bimetallic strips should operate freely and have about the same range of motion at the same temperatures between them (I used a pot of hot water).

I don't think the damper oil makes much difference -- I usually used 3in1 or sometimes automatic transmission fluid of some unremembered specification... simple motor oil is probably the safest. The oil in the dashpots acts to enrich the mixture when accelerating -- the heaver the oil the slower the piston moves up and thus the higher velocity the air going through the carb -- causing more fuel than "normal" to get into the mixture.

They don't have some of the SU HS6 problems like leaky throttle shaft bearings and such. They do have the flaw of having more than 4 moving parts...