Yeah, it should definitely still do the job just fine. And looking at the spec sheet, it's a fairly lightweight battery for its capacity. Also, it's good to see you over here (presumably for info on Sanford's build). I'm Rslifkin over on GRM if you're wondering.
I'm not quite sure that's an AGM. Based on how it's labeled, I'm thinking it's a sealed (valve regulated) lead acid along the lines of those used in UPSs for power backup, etc. Which means it's likely to be either a sealed wet cell or maybe a gel cell. But the price makes me think sealed wet cell.