As far as the use of lifters Ford would have only used a hydraulic lifter on a hydraulic cam, and a solid lifter on a solid cam. The ramps are ground differently depending on the type of cam and using the wrong type lifter on a cam not designed for them will damage them both in a short time. Additionally an adjustable-rocker set would have always been used in a solid lifter cam. I can't say for sure if Ford used an adjustable-rocker set because they ran out of parts for a Hydraulic cam engine it seems a bit doubtful to me but for sure the adjustable-rocker sets have been a popular swap onto a Hydraulic cam engines for many years.
Would be hard to say if you have a Hydraulic cam or not would say you would need to take apart to know for sure. But if you think its running good now than maybe it's okay. If you find with use that the adjustments keeps loosening up than something is wrong. Hydro lifters in an engine that sat for a long can be gummed up etc. With time, use, oil changes they may be cleaned up. Good Luck
