I have never noticed anyone selling any emblem templates. That would be great if they did.
As others have shared, a little creativity can go a long way. I have found the best way to achieve the best results is by using an 'original example' fender (hood or trunk lid, etc.) as a a source for locating the typical original location measurements. Without an original panel, things might get trickey.
After confirming the typical location and/or spacing...I have found that placing and clamping a donor section of sheet metal directly over the holes already in the original (rusted out or collision damage) panel works best, then drilling holes into your new sheet metal section from the back side. (This might be challenging on a hood, trunk lid or behind a fender brace or the likes and may require cutting obsticals out of the way)
Keep in mind that some times, a drill bit can 'walk a little bit' so always use a new, self-centering premium quality bit. The old holes will keep you on track only about +95% so test fit the emblem or pin letter in your newly-formed template and slot any holes found to be off-center in the template (if needed), marking any side of any particular slots that you may have found off-center slightly and when drilling into your new panel, force the drill towards that marking. It isn't a perfect solution but this way should get results closest to your orginal panel as possible.
Obviously, without an original panel with the original holes, the challenge is a bit greater but in my opinion, a person should at least, ALWAYS get measurements from original panels and avoid simply using a rough-guess for any of the locations. You might be surprised how some original emblems were placed slightly different from side to side on original examples
