Probably not deinterlaced at all, just converted from an interlaced master.
Originally Posted by: Zachary
Deinterlaced, converted from interlaced, however you want to put it - they obviously used the field discard/interpolation method, halving the vertical resolution. Given the apparent quality/nature of the source master, it likely just had 2:3 pulldown and could have been converted to progressive with zero quality loss using a proper inverse-telecine filter.
Originally Posted by: Mesterius