Oiler on back of shackles looks as though it is push and turn to revival hole for oiling. Is this correct?
I’m pretty sure 1925s came from Ford with “flip top” oilers. Of course, a prior owner may have installed the wrong oilers at some point. 
Thanks. It looks like a grease cup but when I unscrewed it, cap didn’t come off but seemed to be spring loaded cap and when I further turn it, it at that point, that’s when I saw an oil hole.
By 1925 I think the rear spring shackles and the spring itself just had holes not oilers.
My 1926 has flip top caps. If you just have holes, I would bet the flip tops have been lost.
The flip top oilers are an accessory. Your 1926 originally just had holes.
Mine are all flip top. Guess they were added quite some time ago. Popped a front spindle bolt one out as the spring for the cap had failed to see if what I had would fit. They were too small, but the hole in the top of the bolt was threaded. Grease nipple? This would not be original would It?
A grease fitting would not be original. If you decide to install a new grease fitting there, be sure to pump grease in until you can see it oozing out of both the top and bottom bushings that the spindle fits in.
I didn’t think so and grease pumping would be the thing to do. I wasn’t going to replace the cup with a zirk, I was just surprised to see the threads.
It was common - and not a bad idea - to screw in grease fittings in the holes. I have seen Fords with the Alemite (Generic Motors) grease fittings too. Very common modification.
I pump grease into my spring shackle flip top oilers using a grease needle with a rubber tip until the grease flows out of both ends of the shackle. Larry Smith called it blasphemy, but it works great and doesn’t drip onto the floor. I still use oil on the king pin oilers, I worry about the grease being able to make it to the bottom bushing.
This is definitely something to consider. I agree Cudaman that grease would be a bit less messy, as you say, no dripping. A project for when the snow flies. Thanks for the input gents!