The main.css file loaded by the build pipeline plugin contains 18 declarations that are dropped by Mozilla Firefox (v24). 9 of these are because Mozilla dropped support for -moz-border-radius and -moz-box-shadow with the completion of bug 693510. The changes were released in Firefox 13 on June 5, 2012.

Since Firefox 4, the non-prefixed versions have worked in the browser. Out of curiosity, I looked up when support for Firefox 3.6 ended. Firefox 3.6 support ended on April 24, 2012, with a recommendation for enterprises to move to the extended support release plan.

Given this information, I think it's a safe move to remove the -moz-border-radius and -moz-box-shadow with minimal impact to all users of Firefox.