Aside from the build your own, I would really like to have some of my lasers tested with a spectrometer so I know exactly what wavelengths they are. I live in New Mexico and I’m not sure who could do it. Any suggestions?
If you're able to measure and set up a diffraction grating in a decently precise way indoors (or measure long enough distances and have a large flat wall & a friend to help outside), you could measure your lasers yourself with a cheap diffraction grating ordered online.
Apply a bit of trigonometry and all you need is a grating of known line-spacing and a way of accurately measuring distance.
I'm going to do this at some point as there is a large flat field with a wide building nearby where I live, so I'll borrow a long tape measure (or even better a laser tape measure ) and set up outside for it.