Just as an FYI Testors model paint is a good option.
I have used it on my bike and was able to match every color on my Trek (Dnister Black - Testors Graphite Black Metallic, Viper Red - Testors Gloss Red, Gloss Black, Flat Black). Fortunately, I have only had to use it on a few pencil tip size nicks. You can find it at most craft stores in the US like Michael's, Hobby Lobby, etc for less than $5.00.
I have found usually a cheap precision paint brush - https://amzn.to/2KuUSFr, a steady hand, and a bit of patience can result in some really good results.
vs.
Just eyeballing your bike frame color from ebay it looks like Testors silver without metal flake may match well (Best bet is to hold the bottle next to the bike which is what I did before using it on my frame) - https://amzn.to/37K1NDG.