imho if it's a bottom end rattle (which would be a serious problem and likely warrant gettgin a replacement motor) then it will probably get noticably worse quite quickly over time to the point where its unmistakably that.
The other main causes of the ticking is valve clearances need setting or soemthing to do with the timing chain tension/tensioner.
Setting the valve clearances is by far the easiest to do so if i were you i'd start by getting that done before looking into other options. The valve clearances shoudl usually be set every few thousand miles (see service/owners manual for the actual interval, idk off the top of my head).
To do the valve adjustment you'd need basic tools (sockets, spanners etc) a set of feeler gauges and a set of valve adjsuting tools like this:
Interchangeable wrenches and shafts to give nine different combinations. We apologise in advance for any inconvenience caused. Key Points. Our wide range of tools include hand tools, power tools and many more specialist tools.
It's much easier to set the valve clearances with the motor out of the bike but that's a LOT of extra work, and it is possible to do it with the motor still in the bike, but it is very tight in there because the cylinder head is pressed right up against the frame... its a pain in the ass to do, but managable. I tend to try and do it when I've got the motor out, much easier to do well when you have better access.
If you have a jack or one fo those small motorbike scissor lifts it may be possible to unbolt the upper two engine mounting bolts (but leave the lowest one connected, jsut loosened slightly) and let the motor pivot down slightly to give yourself more room to work on the valves. I've not tested this theory yet but that was what I was hoping to do next time I did mine, though I've opted to just finish the other motor and then get that in
If you dont have a copy of the service manual (which you will need to do the job and details the exact process) then either email me [email protected] and I'll send you one or I'm sure one of the good people on here will also oblige. That will also give you an idea of how difficult it is and whether that's something you want to try and do yourself