depends if that's all a band does, rather like a 'tribute' naming themselves so it leaves in no doubt who you are a tribute too, in this case, if all the band does is slow blues with long guitar solos then yes, keep blues in the title, if not, drop blues from the name.
Reminds me of a conversation I had with a fellow bass player many years ago, "What's your band called then?" I asked, "ZZ Birmingham he replied", "ZZ Top covers band then?" I asked, "No, we don't do any ZZ Top songs"
Another band I knew called themselves Two Guitar Clash, after a Stiff Little fingers obscure B side because they did a lot of SLF songs, of course your average punter thought they did Clash covers