Denti,
this is a major discussion I have since about 3 years, it will obviously never end until the law makes it understandeable.
To certify an aircraft for RVSM operation you will not need TCAS; based on this, your assumption is very correct.
However, aircraft need to have a TCAS system these days and this makes it difficult. It goes down to ATA 34-40 and some CAA have superseded the MMEL of some manufacturers to have the AOC MEL showing that RVSM compliance is only given if an operational TCAS system is available.
You may have to dig a little in your MEL, most probably there is only a sentence in ATA 34-40 similar like "only required if enroute or approach procedures ....."
According to RVSM requirements your MEL should contain a special dedicated section, most probably somewhere in the preliminaries section (or whatever your AOC holder calls it) and the requirements are listed there. A tad confusing sometimes, without TCAS I have to stay out of RVSM.
Hope this helps.