Looks normal to me, a lot of Oncidium alliance plants get spots like that. If they start to spread or grow, then you may have a problem, but I wouldn't be worried.
ditto on Tony. I have a bllra tahoma glacier that has similar small spotting. its recovering right now though. it was one of my very first orchids and lost its roots from over watering.
I don't do most Dendros or large, "floofy orchids". For me it's minis (like Angraecoides), Masdies, Paphs, and others that crept in somewhere along the line. See my orchid list for complete collection (usually not current.)