Can i upgrade to ios 6.1.2 without shsh ??

First of all, i appreciate the great job over this fabulous site. my question: i have iphone 4g ios 5.1.1 jailbroken. on my cydia i have shsh for 6.1.3 shown in my device. and i dont have any other shsh shown except 5.1.1. i wanna update and jailbreak to ios 6.1.2. can i do it without shsh shown for ios 6.1.2 on my cydia ? and if i can, can i do it through this site by following the instruction ? appreciate your help.... and keep going