Identify device from user agent?

Can I identify the model of a Mac by it’s user agent? I understand there are free online services which provide info on the browser an operating system, but can I find anything out about the hardware for the following:

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/536.25 (KHTML, like Gecko) Version/6.0 Safari/536.25

Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:18.0) Gecko/20100101 Firefox/18.0

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_8_3) AppleWebKit/536.29.13 (KHTML, like Gecko) Version/6.0.4 Safari/536.29.13

Thanks!