OEM Nissan Headlight Sealer

has anyone tried this stuff? I ordered a set of headlights off ebay and my friends said I should seal them before installing just in case they start leaking. I did a search and only came up with the clear silicone sealer found at lowes/home depot. I remember someone telling me to get the OEM Nissan Sealer, it looks like a rubber roll of black playdo that you can find behind door panels to keep the plastic sheet on. basically you just push this in between the openings of the headlights. here's a link I found..

http://www.mynismo.com/products/?id=5577

 

can also buy it here.
http://www.theretrofitsource.com/product_info.php?cPath=31&products_id=792

 

Just ordered a roll, thx a lot!