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Could be. Who knows. Blue RTV is a silicone. The stuff I found appears to be grease-based pencil. That's how it looks to me but who knows what happens after 55 yrs. In addition, they were only found on the outer tie rods. Not sure why the inner tie rods wouldn't have it, if it was RTV.
Grease based marker (like big crayon) would not be the way these would have typically been marked if marked. Paint was the typical product and this appears to have some thickness to it - more like RTV would have The RTV might have been used to "glue" the boots in place and keeping them from coming loose.
Can’t tell from your pics but the nuts for the tie rod adjusting sleeves on my October Metuchen car have some type of red plastic or loctite on one of the 6 nut faces. Also, while you’re in there, the end of the center link under the pitman arm has a yellow dab of paint. This isn’t a very good picture, it’s the same yellow inspection color found in other areas.