Old versus modern phono jacks...adapters needed?

So this Xmas my wife bought me a nifty stocking stuffer: a vintage portable reel-to-reel player, circa early 1960s.

And to my delight, it actually works! It came with a mini mic (which doesn't work) and a earpiece (which does) for listening - the tape doesn't have much on it. I want to use it for recording and re-sampling with a new cable for fun, and in my shopping for an adapter, I'm wondering if a typical 3.5mm cable will work. The mic and earpiece jacks are identical and in 3.5mm mono, but are old and look like this (2nd from left):

and not this (again, 2nd from the left):

Will these sound the same as a modern 3.5mm jack? In other words, will there a difference in fidelity between the more rounded old style jacks and the modern ones? I've never messed with recording with such old equipment, I figure someone here might have before or even advice is using an old reel-to-reel like this.

as long as they are long enough to connect each part it should work,

I wouldn't really worry about fidelity more a tight fit and maybe clean with some switch lube in case the jacks have corroded slightly

yeah should work fine with new jacks

Cool, I figured that much. Thanks!