4504 Millennium Falcon question

[ZeldaTheSwordsman]

I recently got the urge to put this set back together again, an urge I finally acted on the other day. It was fun, although it further affirmed my desire to get the Episode VII or Episode IX Falcon. 4504 has never impressed me design-wise (No joke, when I got it for Christmas in 2005 I soon found myself wishing my parents had gotten me 7190 off eBay instead), and in fact I've come to suspect that the design was never actually physically playtested before release.

Anyway, whenever I've built it I've always put a yellow 1x4 plate atop the black 1x6 arch brick in order to anchor the front central roof panel when closed. But I noticed that this step isn't in the PDF of the instructions available on LEGO.com, nor in the version of the instructions currently present on Let's Built It Again. Nor is this 1x4 plate in the Bricklink inventory for either version.
So, my question is: Is this step a mod I've been doing for so long that I forgot it was a mod? Or is there a version that does show adding this? If it is a mod on my part, than the design is even faultier than I've long thought.