The all-important tag, identifying year of manufacture, model and other data, is typically put on the engine.
"But Gade put the tag on the box, and it rotted off," he said.
One way to guess at the age of a Gade is through color. Before 1912, Gades were painted dark green. After 1912, the color was changed to red.
"There were very few Hawkeyes," Gilbert said. "I've only located four."
Gade made an early fortune in land investments. But a second investment, during World War I, proved disastrous when the market collapsed.
The Gades held on to the company until about 1923, Gilbert said, when the employees bought the parts inventory. For a brief time, they assembled a 1 1/2 hp engine. Those efforts subsequently failed, "and the company just kind of disappeared," he said.
More than 60 years later, Gilbert is attempting to put the pieces back together again.
"I've been taking pictures and registering all the Gades I can find out about," he said. "I have friends who'll let me know when they find one, or they'll take a picture for me."
It is the first formal registry of Gades, he said. No other registry or records are known to exist. And although Gilbert collects Gade memorabilia, in all his hunting, he hasn't found so much as a single shipping tag.