Yes, it will have a syn value on a red day - it's only free on green and extra easy. It's not high though, according to my book it's 3 syns for 100g canned.
I didn't find out it was a syn until a few weeks into SW and I hadn't been synning it and still losing so while that's still the case I'll continue not counting it. I'll just know to take that into account if my weight loss stalls.