Will this fit my XPS M1530?

http://www.amazon.com/Blue-500-Mobile-Hard-Drive/dp/B0037NYQ6Q/ref=sr_1_1?s=electronics&ie=UTF8&qid=1359686351&sr=1-1&keywords=WD5000BPVT

It has the same Manufacturer Part # as the one on the dell site http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&s=dhs&cs=19&sku=A3694151&mfgpid=194218&chassisid=8270 but it seems to have different dimensions.

I'm doing a refurbish on my old laptop to give to another person's whose laptop broke and can't afford another laptop, and after the miserable experience I had with Dell and this laptop, I don't really feel comfortable buying hardware from them, but I'm concerned that the dimensions listed on the Dell site are different than the Amazon site, though they use the same images.

Just wanted to make sure before I made the leap.

Thanks for any replies in advance!