Timing chain cover seal install.

I have a slant 6 I am re-doing in my garage. I was wondering if the seal that goes into the timing chain cover has to be pressed in using a special tool or can it be put in place simply by installing the timing chain cover back on the block. Will it seat itself in place? My manual shows me that the seal has to be pressed in with a press tool. The guy at Autozone told me it doesn't have to be pressed on. it will seat itself once it is in place and the cover goes back on the block.