Hey Don,
Actually I was fearing that a lot of users are going to have a problem with the mtupgrade plugin, but this seems not to be the case.
Well, in truth most of my support requests are from people that are unable to turn the plugin on, because they have a 3rd party plugin that blocks it, etc. But once I help them enable it, everything works fine for them.
The mtupgrade plugin is in joomla since version 1.5.19 - I think that this was 1.5 years ago??? So, a lot of developers got the chance to update their software... Why don't you check the support forum of your template provider? Perhaps they already have a working version for mootools 1.2
Kind regards,
Daniel