It does, if there is a modem in the comm slot. I can't 100% vouch for the behavior if there is an Ethernet card in the slot.
However, you would just use the Printer port for localtalk and make sure you select that in the AppleTalk control panel on the 6200.
Without a little extra You won't get the SE/30 talking directly to the iMac, but you could either use the 6200 as a client to both, or the 6200 as a client to the iMac and the SE as a client to the 6200, or, if the 6200 is the bridge mainly, use it as the server to both.
It depends on what you "need" though. You won't [easily] get TCP/IP this way, just file services. That's a huge boon for compact macs, but I do know an SE/30 can be expanded enough to where TCP/IP (with OpenTransport, even) is reasonable on it. It's worth keeping your eyes out for an ethernet card. They do exist for that Mac.
SCSI ethernet is another extant option.
There are also IP to Localtalk bridges, I forget who it was but someone mentioned running one on an old Cisco router, there was a software one, so if you want to put some effort in, that might be worth it. It'll be a little faster than dial-up as well.