Yeah 1.7.2. I think some are available for 1.7.4 and 1.7.7 etc.
But don't you need MCP for decompiling?
You can decompile manually using JAD or Fernflower (MCP uses those as well).
However, MCP also deobfuscates the source. Without deobfuscation you will get code with meaningless names like "ck" or "ae" or "vl". For small mods it's OK, but in case of SSP and OldDays it will take a VERY LONG time to update it like that. Probably much longer than it takes for Mojang to release new major version.