Employment probation period & Green Card

I've been offered a position with a tech company in Ireland, and they will sponsor me for a Green Card. I've received the contract last night, and it has a clause regarding a probation period, as per the Employee Handbook - 6 months, which can be extended to 10 months.

Now, I now that one of the requirements for a Green Card is that the offer of employment is for at least 2 years. I've asked the company about this, and they said that they will state in the application that the offer is for more than 2 years, but that 6 months' probation is standard in Ireland, and shouldn't be a problem for the Green Card.

Are they right, or do I have cause for concern?

Yes they are right. Probationary period is part of every employment in Ireland especially in the professional jobs.