Where's Marti when you need them. 351W/C 4bbl in 69 was a funny one. Some very late one got the Cleveland because they ran out of 351Ws. That why they dropped the 351W 4bbl due to unhappy customers getting 351Ws when they wanted Cs.Wouldn't the answer be possibly? As 351Cs were rare in 1969, as production ramped up and as evidenced by 351W being installed in H code Cougars, it would be unusual to find one in a 69.
To verify that they existed we would need to see pictures, including vin and data plate details and casting numbers.
Would be neat to discover that it had happened