Matching Glenn's conversion rate is a big ask for any striker but thankfully isn't necessary. I'm hopeful Maupay (or someone else) will take more shots than Glenn, having got in behind the defence more frequently.
I'd imagine they just take a look at the goals tally on wiki before checking out the wag on Insta. Then it's just a quick scan of the Fifa stats, maybe a youtube vid if time allows, before tabling a bid.