Visit
www.gibson.com. Compare and contrast the specs of the Gibson and Epiphone Thunderbirds. Everything in the description of the pickups on the US model screams Bartolini. The Alder body and screwed-on maple neck of the Epi screams Fender. (Have you guessed where this is leading?)
Measure the pickup routs of the Epiphone. Visit
www.bartolini.net. Somewhere amongst the section on pickups for four string bass there must be a dual-coil soapbar model that fits the Epi routs.
Alternatively, consider EMG. Some models feature a Fender-style pickup inside a Soapbar housing. Others mimic the Musicman Stingray pickup. Hence, numerous PJ, JJ, MM/J, HB/J permutations arise.
Right now, your bassist has the opportunity to select how his instrument will sound whilst retaining the T Bird looks and feel. Realising that college guys are not wallowing in disposable income, I suggest that just one pickup is purchased.