Ming, you would be surprised at how much "Chance" glass, "positively identified", emanates from ex-Chance worker's homes. The trouble is, not all of it is by Chance... this bases the assumption that every bit of glass coming from a former Chance worker's home was made by the company.
The point is, I based the findings in my book on evidence from vintage trade magazines and reliable first-hand sources, like Tony Cartwright, and not relying too heavily on word of mouth - see Appendix 1, where I list all my findings and the earliest date each pattern was recorded. The latest pieces of Chance glass are also now approaching 30 years old, so spoken evidence really is unreliable, particularly third-party evidence (e.g. "my mom said so"). Also consider that the 'Illusions' range (1971, p54) was promoted through these magazines, but I have only ever seen one actual example and I own it.
It is possible this tray is by Chance, but I have never found any evidence to support this. However, I have directed Tony to this thread to see if he can recall it.