Warriors host last year's champions at Scotstoun having lost three of their last four games, including an away defeat by the Welsh region.
Speaking to BBC Scotland, Seymour said: "That probably was a good thing to happen to us. We've learned a lot about ourselves as a squad.
"Credit to the teams we came up against. They played really, really well and they managed to get the better of us on the day, but it's given us a lot of other things to look at and other little weaknesses we haven't focused on to try and strengthen up. Hopefully we'll see the improvements come Friday."
Dave Rennie's Warriors have won each of their 10 home PRO14 fixtures this season, taking a bonus point from all but one.
"You try and take key points out of every game you play," Seymour added.
"We'll be looking back at that footage and seeing what we did wrong and what they did right and we'll be trying to fix things and fingers crossed it'll be a different result at the weekend."
Seymour says the squad are determined to send the leavers off with the PRO14 title.
"We had the leaving dinner last week and there's obviously a seniority and quality we're losing in the squad," the Scotland wing said.
"We'll look to get a big result for all of those guys and hopefully this won't be the last fixture we'll be able to do so.
"I think when you get down to the crux of it, it's knock-out rugby from here on in and there's no second chances. Finals rugby is a different kettle of fish, so both teams will be going out there to get a result.
"I've no doubt in my mind that Scarlets, especially after becoming champions last year in Dublin, will be looking to retain the title."