Sorry, Rick, I've seen Erusta razors before and tried to find out some history. I've picked up snippets but nothing conclusive. For what it's worth everyone who owns one seems to like it and that's a nice one.
Here's what I've found in case anyone is motivated to research further or it may provide more clues.
Almost all the Erusta razors I've seen are stamped with "96" and "Boehler Steel"
I came across an identical razor stamped "Eastern Cutlery Corp." instead of Erusta but with "96" and "Boehler Steel". I couldn't find anything on Eastern Cutlery except that they sold other models of razor that were made for them by Boker.
I also came across a Razor that looked similar marked "91" and "Boehler Steel", in the same script and script positioning, that was branded "Vipel" instead of Erusta. Couldn't find anything on Vipel either.
There was a NOS Erusta sold about a year ago that had a warranty paper with the box. The warranty had the registration number 15923 (German). That's possibly traceable, but it's more work than I'm prepared to do right now.
From what I came across, Erusta razors seem to date from the early 1900s to around 1950.