Yes, the date of recognition for you as a beneficiary would be the same as the trust's date of recognition. Since you weren't a Colorado resident at that time and the income wasn't Colorado sourced (both the trust and property were outside Colorado), this long term capital gain wouldn't be taxable by Colorado.
According to Colorado tax code (section 39-22-109), income from trusts is recognized with the trust recognizes it, and for nonresidents only Colorado-sourced income is taxable. Since this capital gain was both recognized when you weren't a resident AND wasn't Colorado sourced income, it will not be included in your Colorado income when determining your Colorado tax.
