I have pre-discovery CCD images of SN 2014bc in M106. Although I used LRGB filters, a supernova researcher whom I know believes that it would still be worthwhile to perform photometry on the supernova. The SN is only a few arcseconds from M106's bright core, so he recommends subtracting pre-supernova LRGB images from my own images in order to better isolate the flux from the supernova. If anyone has old LRGB images of M106 that they'd like to share, please let me know. I would prefer images with a pixel scale of 1.5" / px or less.
If the quality of the photometry is high enough, the professional astronomer believes that it would be appropriate to post the measurements in an ATel, and if we use your images of M106, we would list you as a co-author. Thanks!