Quite true. Depends a lot on the internal design. Many of the old "Midland/Calrad/Realistic/et al." CB SWR meters from the 60s and into the 70s were designs that will work fine at VHF and they're actually more sensitive at VHF than at HF because they used stripline couplers that had more coupling at higher frequencies; as such even a few watts at VHF could drive them to full-scale for the forward reading, although it might take more than 100W on 80m to do that. I'd just "try it."