missed replacing the hd cover

I bought a replacement 60Gb hard drive for my iPod Video locally to avoid shipping and customs costs (Canada). The drive did not come with any foam attached or metal cover over the circuit board. iPod 第5世代 (Video) ハードドライブの交換 I peeled the foam off of the original drive and used it on my replacement drive, but it didn't occur to me that I could also peel the metal cover off of the original drive and use it over the circuit board of the new drive. Instead I placed the foam directly on the circuit board and completed the repair. My iPod now works great, but I'm concerned about that foam being directly in contact with the hard drive's circuit board.

Should I be concerned?