Similar is not same. The Marriott credit card just dumps 15 elite night credits (annually) into your account. But that alone gives you hardly anything (just the Silver level, which is not much at all). So unless you already have 35 other Marriott elite night credits, so that adding 15 would make you Marriot Gold (the "sweet spot" in Marriott status), there's no immediate effect to be seen, the way it is with the Priority Club/IHG Visa giving you the full top-level status in one step.

However, if you meant simply that you don't know your Marriott Rewards number because you hadn't signed up for it before signing up for the Marriott card, yes, you have to call either Chase or Marriott (Marriott may able to look you up by name).