WD3200BEVT new drive screws do not align with hard drive tray

I am replacing a WD3200BEVT with another one and the screws do not align with the tray!

Upon receiving new hard drive, I notided that the extensions after main part number were different - is this the main reason or did WD change the height of the standard 3200BEVT hard drive?

Is it okay to install new hard drive, place in tray, place in laptop computer and NOT have the screws in  place from tray on to the sides of the hard drive?

Please assist.

Thanks.

Are you sure they are the same model?  There are THREE 320gb Scorpio Blue models, 2 are SATA, one is PATA.  They are slightly different physical sizes.