Maybe. Resume-shufflers definately won't, and test 486 is unlikely to show up as a requirement in many job req's as a requirement. But I put my certification(s) in a seperate section of my CV with the full title of the certification and/or the exam title. It helps document that I know what I know and I'm not just another smoke-blower....
Will it help with recruiters? Maybe, but it's doubtful - while I think that UML is a useful skill to have, I don't remember many ads when I was job-hunting looking for folks who know UML. (Though, when we were hiring most recently at my company, it was something that earned extra points when we saw it on a resume.) However, I would also say that I think the certification is definitely worthwhile in the sense of documenting what you know, and proving some competancy with the skill, as well as showing your employer (or potential employers) that you are able to apply UML in some non-ambiguous fashion.
Theodore Jonathan Casser
SCJP/SCSNI/SCBCD/SCWCD/SCDJWS/SCMAD/SCEA/MCTS/MCPD... and so many more letters than you can shake a stick at!