The small film caps that are put across the electrolytics, are bypass capacitors.
A small high quality bypass cap can greatly improve the SQ from the bigger electrolytic.
I recently recapped a tube amp and I put Myflex capacitors with great success.
Also recapped a Marantz 7T and because of space restrictions, used Audionote electrolytics with Myflex bypass capacitors on each one. Also sounds fantastic.
Deoending on how long you plan on keeping the amp, buy the best capacitors you can justify putting into it. They will make a difference. Humblehifi’s capacitor list has served me well in the past when deciding on what caps to use.
And ignore the comments about your amp not being worth the effort. It’ll be worth the effort. Anyone who has done a recap, either themselves or by a tech will tell you it’s worth it.