Fuel pump missing piece

[iBoostDSM]

I went to install my Walbro 255 and noticed that it's missing a piece that my new 190 had that I just sold. On the 190 there was a large silver piece on top so that the white cap could fit on it snugg. The 255 didn't have that, the white piece kind of flopped around and just fell off. Is it ok to install it without it, can I try to pop that piece off the stock one and put it on the 255?

 

[iBoostDSM]

Here's some pics to help out. The silver piece should be at the top, under the white cap, the picture in the link does have the silver piece.

http://www.dsmtuners.com/classifieds/attachment.php?attachmentid=43374&d=1305088283