If it's an 850MHz system you can assume it's "wide"; if it's 900MHz, "narrow". For VHF/UHF, I'm not aware of what the rules are except that the UHF Enbridge system is "wide".
The Sarnia EDACS system is the same as the Chatham-Kent system as they are both owned by Thames Communications in Chatham. Sarnia and Lambton County Fire are on the Lambton system and CK fire and CKPD are on the Chatham-Kent system. These systems are somewhat mislabeled in the RR database as they are privately owned commercial systems that are being used by local emergency services (man is airtime ever expensive)
They also have commercial clients who are getting great coverage out of a commercial system designed to have almost 100% area coverage for emergency services.
They have a third system in the Belle River area that they are trying to sell space on. Maybe one day they'll actually link all three sites together to make an even bigger regional system. In talking to the techs at Thames all they have to do is hook the three controllers together at each site to make that happen.
I should say that the Lambton and C-K systems are the same setup with respect to the 800 MHz EDACS system as well, just operating on a different set of trunked frequencies at each site of course.