it depends what they are, but i would say yes. i own a large batch and they are the shortes mobis you can have, and short is great for mobile
plus, just randomly check on google for things like t4, a2 etc
there's loads of firms with these type's of names and only one can own the com
for many new firms they just be happy with the mobi and if you don't price too high could be a lot of these new firms or existing firms wanting a mobile address or just rare short name to fit their company name
when 5-a etc were regged in com a few years ago for $7 i bet everybody rubbished they would get $800 etc for them, obviously real meaningful ones like a-1 , a-4, 2-u etc would be worth even more.
don't expect miracles in short term but def. worth the renewal, blimey