Just picked up my GT Semi rigid boot liner today and i also thought it was the wrong one as it didn't seem to fit correctly on the left hand side where the Bose sound system is located.
Anyway quick trim with a sharp blade to cut off the tray element of the liner and hey presto it fits like a dream.
I used the lower side of the ridge of the tray as my guide on where to cut, so that it would match up with the ridge of the other side.
One tip if your unsure of where to cut, take a little bit off at a time you can always trim a bit more off if doesn't quite fit. Common sense i know but worth bearing in mind.
I've had the car for nearly a year now and wish i'd bought one sooner, looks the part with the embossed Alfa badge in the middle and the GT lettering in the lower right hand side, also got a bargin only paid £30 for it, not bad going for a genuine Alfa part.
I bought it from the following website which is part of the Stonearce Motor group, even got it delivered to my local Stoneacre garage and picked up from there saving on delievery.
They do a lot of well priced Alfa parts and accessories might be worth a look.
Alfa Romeo GT