Yes for sure.
I seemed to have lucked out with Amex
I originally just had one gold card back in 1983.
I would think only one card would count towards back dating.
But I am new to all this.
I am surprised they even gave me these cards with such a thin history.
I will just use them lightly so they report to the CRA's and hopefully get increases in my credit limit as the accounts age.
Amex Zync NPSL 9/12, Amex CostcoTrue Earnings $10K 9/12
Amex BCE $3K 9/12 (Amex Back Dated to 1983)
Chase Sapphire Preferred $17K 11/12, Chase Freedom $7K 11/12
Discover More $750 11/12
CapitalOne Platinum Secured Card 2K 2/12 (Closed 12/12)
FICO: EQ = 804 EX = 802(Amex) TU = 801(Discover)