As others have said, two unneutered males can NOT be safely kept together. There's no guarantee that they can be bonded even after neutering (+6-8 weeks for a male's hormones to totally dissipate), but without neuters, it's a lost cause. The fights can get vicious or even deadly. I'm talking penises bitten off, entrails ripped out kind of deadly.
Protocol varies from shelter to shelter (same for rescues), but the answers you get when calling can also vary from one employee to the next. You can always try calling on different days or asking to talk to someone about scheduling an appointment to surrender your rabbit (you can always bluff, worst case scenario you can hang up). I know the Houston SPCA makes you meet with a counselor before surrendering a pet to discuss alternatives... and a shelter would much rather help you find an affordable spay/neuter than have another animal they have to care for indefinitely.