That's for sure. Here's what an Ettus B210 (now $1472, not cheap) looks like with a fundamental at 145 MHz. 3rd harmonic is only 10 dB down. Power was 0 dBm (with a 20 dB pad on the analyzer input).
That's even worse than I thought it would be. A cheap one will likely not do better. At least they picked the HAM bands smart so harmonics tend to end up in the next HAM allocated frequency range up. But SDRs being what they are there are no passive components on board to ensure the signal stays 'in its lane'.
It's inherently a broadband device, with no output filtering. No surprise that the output is full of harmonics. I built several application specific RF front ends for Ettus SDR's at a previous job, it's mandatory for any kind of professional use.