I added opening_hours=Mo-Sa 08:00-18:00; Su 08:00-16:00 5 years ago, probably because there was a sign then. Today I couldn't find a sign, so SC added opening_hours:signed=no The opening hours are likely to still be correct so shouldn't be deleted.
There's another shop with almost the same name (so probably the same company) a bit to the east which still has a sign, with the same hours, so the opening hours are probably still correct.