It wouldn't have to use the newest version. If the version has already been specified, say with *NetInstallModule, then it could take it from there. But then there's the trouble of how it would know whether you wanted it to guess the version or wanted an actual module that doesn't have a version.

NLM 2.4.3 (which is pretty much ready, I just have to package it up) will allow you to use:but it's a bit fragile because of the flaky nature of $constants$.