My 1983 O'day 30 came with a bow roller. However one of the previous owners installed it by cutting out the space where the forestay strap sits, thus centering everything. I understand why (as previously stated that the area up front is really congested), but this is not a good idea as the anchor then rubs against the forestay turn buckle and can cause other issues.
I need to look at it properly, give it the true sailor stare, think it through and then build my solution. I might end up butting a new one against the old old one, to off center the anchor.