[Tiara Sovran] What size Duckbill

[Feetwet]

I have a new to me, 2004 Sovran 4400.  The front head is not flushing and I want to replace the duck bill values  The pump is hard to get to, and I can't find a pump model number.  Can anyone tell from the picture if I should order 1 1/2 or 2" duckbill values.  I see both options available online.   

I also see some pumps have two values, and some have four. This looks like two to me (one each side of pump) 

I am not at the boat to measure the size.  Thanks, Rich